Filter



FIG. 1 is a top right perspective view of a filter, showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a side view thereof; and,

FIG. 7 is an opposite side view thereof.

The broken lines depict portions of the filter which form no part of the claimed design. 

CLAIM The ornamental design for a filter, as shown and described. 